1. Field of the Invention
The present invention relates to an antenna apparatus for a radar sensor that has a plurality of individual antenna devices that interact through interference to generate/and or receive a radar beam. The individual antenna devices are provided with a radar signal that is generated by a feed device. In addition, the application relates to a method for electronically pivoting a radar beam, wherein the radar beam is generated through interference of radar signals that are emitted by a plurality of individual antennas. Furthermore, the application relates to a radar sensor having such an antenna apparatus with which such a method can be carried out, as well as an aircraft having such a radar sensor.
2. Background Information
Antenna apparatuses of the kind initially specified are used as radar sensors in radar devices to detect surface structures of solid or liquid materials. This application is particularly interesting for use as an obstacle radar in aircraft. Here, the shape of the radiating antennas focuses the high-frequency electromagnetic waves, which are usually referred to as radar waves, by means of interference and by means of beam formation such that their propagation is limited to a relatively small solid angle. In a sense, a radar beam is generated with which objects can be scanned.
Likewise, radar signals received by the antenna apparatuses can be combined in such a way that it is possible to filter the signals whose propagation direction forms a specific angle to the antenna apparatus using phase shifting of the received radar signals. This angle to which the reception is limited is referred to as the reception lobe.
In order to generate a three-dimensional image for detecting obstacles with a radar sensor, the antenna of the sensor can either be moved mechanically in two dimensions, that is, horizontally and vertically, or the radar beam can be pivoted electronically. Known imaging obstacle radars that are, for example, sold by the company Honeywell, have limited image resolution due to the use of low frequencies and are comparatively geometrically large, since the antenna devices that are used particularly have large spatial dimensions due to the wavelengths of the radar waves that are used. Radar systems that use higher frequency ranges to achieve a higher image resolution (for example, Sandblaster from Rockwell Collins) have mechanically pivoted antennas that also require a large amount of space.